Field
Aspects of the present disclosure relate generally to charge pumps, and more particularly, to charge pumps with extended output control voltage ranges.
Background
Charge pumps are commonly used in phase locked loops (PLLs). Typically, a charge pump receives up/down signals from a phase frequency detector (PFD) based on detected phase differences (errors) between a reference signal and a feedback signal. The charge pump charges/discharges a loop filter based on the received up/down signals to produce an output control voltage for a voltage-controlled oscillator (VCO).